Liquid fuel burner system



April 9, 1946 E. '.1. sENNlNGER LIQUID FUEL BURNER SYSTEM 5'sheets-sheet 1 Filed Jan. 27, 1942 INVENTOR.

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April 9, l946- E.Y J. sENNlNGER 2,397,987

L-IQUID FUEL BURNER SYSTEM April 9, 1946. E. J. SENNINGER 2,397,987

LIQUID FUEL BURNER SYSTEM April 9, 1946.

Filed Jan. 27, 1942 E. J. SENNINGER LIQUID FUEL BURNER SYSTEM 5Sheets-Sheet 4 Hrryg,

April 9, 1946 E. J. SENNINGER LIQUID FUEL BURNER SYSTEM y Filed Jan, 27,1942 5 sheets-sheet 5 Patented Apr. la, 194s orties LIQUID FUEL BURNERenormi.

Chicago, lli., assigner to a corporation oi Illinois Application Jenneryet, isis, sel-iai no.' esi-ssi Earl Joseph Senninger, SanmyerCorporation,

as c (menswear on the lines o o, sofia g This invention relates toliquid fuel burner systems and has for its principal object to maire theburner come on with a very small lire when it starts. built up to thesize required by the de1 mand and modulated between high fire and low re-in accord with the varying demand for heat.

The preferred improvement of the invention specifically disclosed inthis application is defsigned especially for use with the scheme formingthe subject matter of my companion application, Serial Number 428,390,iiled concurrent- 1y! of variable capacity subject to a suilicientpressure of primary or atomizing air and the delivery of secondary aircan be varied, by opening and closing the inlet to the ian or blower.

Generally speaking, the object of this invention is attained by makingthe pressure of primary or atomizing air act with appropriate delay atstarting to increase the delivery of fuel and air to the v burner andafterwards making the temperature or pressure in the space to becontrolled vary the etlect of the primary air pressure on the deliveryof fuel and air in accord with the varying demand for heat.

in which fuel is delivered by a metering pump the chamber i-i i,iii-uit, respectively, of Fig. 7.

But these specific illustrations and theicorre spending description areused orthe purpose oi disclosure only and are not intended to imposeunnecessary limitations on the claims, or confine the patented inventionto a particular use.

General description In the diagram (Fig. 1) a main housing I0 provides atank or reservoir Il, for lubricating oil, a chamber it for primary oratomizing air above the oil tank, two air filters or cleaners and oilseparators I3 and I4, and a secondary ran or blower casing I5,communicating'with a horizonr tally directed draft tube l`6, passing outthrough l2 and within which are the following parts, which have beendisplaced and shown below in the diagram;

The primary air line Il, supplying the nozzle i8, the oil line I9 withitsassociated heater 2t, also delivering oil to the nozzle I8, and theelectrodes 2i associated with the nozzle for igniting the mixture `ofoil and air when the burner is started.

Furtherobjects and advantages or the invention will appear as thedisclosure proceeds and the description is read in connection with theaccompanying drawings, in which Fig. 1 is a diagram of the system withthe parts displaced in such a way as whole in one drawing;

Fig. 2 is a side elevation vof a commercial burner unit embodying theinvention with a portion oi the modulating motor broken away;

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 2;

Fig. 3a is a perspective view-o! a disk forming part of the means foradjusting the capacity of the oil pump;

Fig. 3b is a perspective view of a crank cooperating with the disk shownin Fig. 3a;

Fig. 3c is a perspective view of the end portion of the oil pumpcasing;

Fig. 4 is a vertical section throughthe commercial oil burner unit shownin Fig. approximately along the axis of the draft tube;

Fig. 5 is an enlarged longitudinal section of the burner nozzle andassociated parts;

Fig. 6 is a transverse section on the line 8 6 of Fig. 5:

Fig. 7 is an enlarged longitudinal on the line 1-1 ofFig. 2, and

Figs. 8, 9, 10, 11, 12, are sectional views taken section taken toreveal an organic 2, taken The main housing also forms a support for anelectric motor 22 which drives the secondary air fan or blower 23, aprimary or atomizing air pump 24 and an oil pump 25, here shown asarrangedA in alignment crosswise to the main housing.

The secondary air fan or blower 23 takes air through the slotted sidewall 23 of the fan casing i6 under control of the rotary shutter `21 anddelivers it through the draft tube I6 around the mixture,` of oil andair discharged from the orice 230i the nozzle I8. The volume is variedby adjusting the rotary shutter 2l.

The primaryl or atomizing air pump 24 takes air in at 29 and delivers itthrough a pipe 30 into the upper portion of the main housing through thefilter I3, which is charged with bronze wool,

Vinto the chamber I2 through which it passes over the supply oflubricating oil 3| and up through the iilter I4 out through the pipe 32leading tov the airline i'i. In fact, that air line,.the pipes 30 and 32yand the chamber I2, may be considered as forming a single air line witha storage or pressure chamber in an intermediate position which insuresan even dow to the nozzle and forms pressure for several other purposes.

The lubricating oil tank II is connected near the bottom by a pipe 33with the pump 24 and by reason of the air pressure within the chamber I2oil from the supply 3i in the tank Il is continuously delivered to theair pump. as a result. this 2' pump delivers a mixture of air and oil orair and oil foam to the pipe 30 whereby the bronze wool In the iilter I3is'made to serve as an oil separator and an air cleaner and thelubricating oil collected there drops down over the outside of the drafttube I and returns to the tank vI I. The lter I3 is separated from theillter I4 by apartition 34,

and the air compressed in the chamber I2 passes up through a second massof bronze wool in the filter I4 before entering the pipe.32.

In practice, the apparatus is so designed that a pressure from fivepounds to twelve pounds,

.for example, may be built up and maintained in the chamber I2. Thepressure in the primary or atomizing'air system is regulated by a bypass35 connected across the inlet and outlet of pump 24 and controlled by anadjustable valve l36. In

this diagram the bypass is shown Aas external piping, but in practice isworked out through the body or casing of the pump. l

The oil pump 25 is preferablybuilt formetering purposes only and shouldnot be used to draw oil from the storage tank.- Where gravity feedcannot be used, auxiliary pumping equipment 31 movable in the cylinder40 serves to connect the line 38 with the line 4I or with the bypass 42,as

occasion may require. The piston is associated with an air motor, hereshown as a Sylphon bellows 44 located in the primary air chamber I2 andsubject to the pressure in the chamber. As a result of thisarrangement,oil from the pump.25 is bypassed back to the supply line until there issuiiicient pressure in the air chamber I2 Electric power for the liquidfuel burner system described maybe taken from the house line 45 loperation.

andthe apparatus shown in the diagram will be understood from thefollowing description of the When the room thermostatror boiler control46 calls for heat Minneapolis-Honeywell R 117 relay` 41 will beenergized and close an electric circuit to the delayed action switch 43allowing current to ilow to the oil heater 20 and the ignitiontransformer 49. After a delayed action, for

example, twenty-five seconds, switch 48 will close the circuit to motor22, which will start the sec ondary air fan or blower 23, the primary oratomizing air pump 24 and the oil' pump 25. While theA pump 24 isbuilding up the necessary pressure in the chamber I2, oil from the pumpis recir culated through the bypass, and the heater v2Il is conditioningthe.ol l in the pipe I9 and warming up the associated parts of theburner. When the pressure in vchamber, I2 reaches the selected amountthe Sylphon 44 will be compressed and the pistonvalve 43 will cut outthe bypass 42 and connect up the oil line leading to the nozzle I8. Asthe'mixture of air and atomized heated oil is discharged from theorifice 2l of the nozzle, sparks from the electrodes 2| furtheried bythesupply of secondary air deto insure delivery of a proper amount ofprimary or atomizing air 'to the nozzle I8, when the pressure in thechamber I 2 will overcome the Sylphon 44 and shift the piston valve to aposition in which it connectsthe pipe 39 with the pipe 4I and that, withthe pipe I 9, becomes one oil supply line from the pump to the nozzle.When, for any reason, the air pressure in the chamber I2 drops belowthat for which the device is designed and adjusted, the piston valvewill shift to the right, cut

oil the supply of oil to the burner and connect the pump 25 with thebypass 42.

By making the presence of a. considerable amount of lubricating oil inthe primary air pump 24 necessary to seal it and give it the requiredcapacity, it becomes impossible to run the p ump long with insuilcientlubrication for, as soon as the pressure in the chamber I2 drops belowthat required, thesupply of oil is cut olf and the control of any one ofthe customary forms will put the apparatus on safety and shut the burnerdown entirely. The presence ofthe 'lubricating` oil in the air pump 24in such quantity as to form a foam makes it possible to provide a veryeilicient filter with the bronze wool in the filter I3, which alsoserves as an oil separator and delivers the excess of oil back to thesupply in the tank I I.

Any one of the many types of oil burner controls may be used with thissystem and none will be described in the interest of brevity. It will besulcient vto refer to Oil Heating HandV Book," by Hans Kunitz, secondedition, and "The Starvbuck Oil Burner Manual, 1941.

- its pressure against the piston 5I.

- ance of livered by the fan or blower 23-through the draft tube is.After a short interval relay u win shut oiilthe current to the ignitiontransformer 4 9. 'I 'he resistance of the heater element 20 increaseswith the rise4 in temperature and the wattage drops to the selectedlimit for the particular design.

` -Mention of Minneapolis-Honeywell R 117 relay is merely by way ofexample. Many other controls can be used and-some other controls must beused when the lire adjusting apparatus, later described, is associatedwith the burner.

' Adjusting the fire According to this invention, the operation of theapparatus described is modied to make theV burner come on with a verysmall fire built up tothe size required by the demand and thereaftervary with the varying demand. One embodiment of means to that endincludes an airmotor comprising a cylindern50, equipped with a piston 5Iwhose piston rod 52 runs through `the guide 53 and has one arm 54connected by a, link 55 with the rotating shutter 2I`oiI the secondaryair fan or blower and another arm 56 connected by a link 57 with a lever58 on the oil pump 25 by which its capacity may be adjusted and enlargedas the shutter 21 is opened to increase theV delivery of secondary airby the fan or blower 23.

'Ihe piston 5I is normally urged to the position shown by a spring 59and its limit in that direction is determined by a low fire stop 60, itslimit in the other direction being determined by a high re vstop SI,both adjustable on the piston rod 52 and made fast by set screws or thelike.

In order t`o move the piston against the resistspring 59, air from thechamber I 2 is conducted by a pipe 62 and delivered to a head chamber 63 in theair end of the cylinder 50 from which it passes by a port 64into the cylinder and exerts The length of needle 65 will time intervalthe pipe 62 and the adjustment of a make the flow of airinvolve thedesired for response to change in demand. and

the supply of air and oil will be increased or decreased in relation tothe pressure permitted to build up against the piston head, thisfunction,

ignite it and the flame is however. being limited by the adjustment o!low fire stop B and high fire stop Bl. In some designs, the length ofthe pipe 82 will have a-negllgible effect and the control will beeffected chiefly by adjusting the needle valve t5.

with this arrangement the burner will, startl check valve Il, back tothe chamber l2 and be discharged through the nozzle.

However, it is preferable to add a modulating control, one embodiment ofwhich includes a pneumatic temperature or pressure device 68, connectedwith the cylinder 5B by a pipe 89, ending in a nozzle 1.8, when thetemperature or pressure of the device il, or the space to which it issubject. reaches the point at which it is set. the arm ll will uncoverthe oriilce l0, allowing some air pressure to such a point that it willnot overcome the force of the sprint Il and furthermore, the needlevalve 85 ofthe modulating motor prevents the pressure which is built upby the primary air pump prior lto ignition from throwing the modvulating motor oi! of low fire position. However,

to escape, thus lowering the pressure in the cylinder 50 and allowingthe piston to move toward the air end of the cylinder under the actionof the spring 59, thus reducing the supply of secondary air and oil. Thepiston will adjust itself'to-some point between high hre and low firepositions, depending on the demand indicated by the arm ll. If thetemperature or pressure at the device 68 should drop or increase, theport 10 will be opened or closed correspondingly and, hence, the re willbe adjusted to correspond with the demand.

'Ihe device B8 may be any pneumatic control that will open a port on anincrease of temperature or pressure and bleed. the air from the line 69to the atmosphere, or close the port on a decrease of temperature orpressure, such, for example, as Minneapolis-Honeywell L-092D. Thesedevices are available in a number of scale ranges and may be used as awarm air control by mounting in the air stream, as an immersion aquastatby inserting it in the liquid to be controlled or as the steam pressurecontrol, by mounting it in the boiler water just below the water line.The boiler water temperature changes with the steam pressure inaccordance with familiar steam tables. As these devices and theirapplications are familiar, specific disclosure is omitted in theinterest of brevity.

To summarize the sequence of operation which takes place whenever theburner is started:

First, the thermostat 48 closes the circuit through the relay 4l whichin turn causes current to flow through the heating element 20 and to theignition transformer 49. After a given time interval, for exampleseconds, the circuit through the electric motor 22 is cclosed whichstarts the primary air pump 24, the secondary air blower IE and the oilpump 25. In approximately two or three seconds after the air pump 24 isplaced in operation, the pressure in the chamber I2 is suiiicient toopen the fuel valve to the nozzle and the fuel in the oil lineimmediately adjacent to the nozzle has, in the meantime, been heated toa temperature which is sufiicient to bring about quick ignition whenatomized at the nozzle and subjected to the ignition spark. When thefuel valve is opened, causing oil to ow to the nozzle, the modulatingmotor is at low fire position, as shown in Fig. 1, because the escape ofprimary air through' the nozzle prior to the opening of the fuel valveholds down the primary air 'as soon as the oil begins to flow throughthe nozzle, a back pressure is created in the primary air line which istransmitted through the needle valve to the modulating motor and withina few seconds. say three or four seconds, after ignition has takenplace, the piston 5| of the modulating motor begins to move slowlyoutwardly 5 thereby gradually building' up the re to the' desiredlpoint. This Vgradual building up of the ame from a low nre start to thesize of flame called for by the burnerload demand (which maytake it or2u seconds) is very important for proper operation of the burner becauseexperience shows that a sudden change from low fire to high fire at thebeginning oi burner operation will' cause the stack to choke and set upbackl pressures which will cause smoking and otherwise interfere withproper burner operation. Ey gradually building up the llame from a lowflame which is easy to ignite to a higher flame gives the hot gases achance to clean out the stack of cold air Referring to Figs. 2, 3 and 4,it will be seen that the bottom of the main housing is formed by la basel2, having a downturned edge 'i3 and a machined ribld ony its upper faceto receive and be secured tothe bottom of thegenerally rectangular walllil, which surrounds the lubricating oil space and with the base formsthe oil tank or reservoir il.

Justabove the lubricating oil tank, and at the-` right in Fig. 3, thereis a hollow cylindrical projection 16, open at ll, to receive the airoperated shut-oil valve for the oil supply.

Above the projection 1I is a larger hollow cylindrical projection .18,the right side of which, in Fig. 3, is formed by the slotted wall 28and'the left side of which is formed by the partition wall 19, which iscurved at 80 to form the throat orentrance to the Siroco fan or blower23.

The draft tube- Il intersects the main housing somewhat below the midportion, and the lower wall 8l, Fig. 4 of the draft tube, extends acrossthe main housing above the lubricating oil tank Il and, in ehect, formsthe upper portion of the chamber for primary or atomizing air.

an air pressure gauge 85. The bronze wool which really forms the:llterlnlzy and oil separating elements of the filters I 3 and Il, fillsthe spaces above the draft tube divided by the Wall 34 and closed by thecap 84. Removing that cap permits access for cleaning the bronzewoolpwhich should be done at suitable periods by remover and man.'v

respect to the fan' or er into and through the draft tube I8.

iJust below'the fan 'casing l5 and opposite to the draft tube the mainhousing has an opening threaded into openings forming propercommunication with the interior of the cylinder 40, which will beunderstood without speclc description.

The right end of the cylinder 40 in Fig. 3`is closed by a screw-headedcap I|5 which serves to compress a spring IIS against the end of thepiston 43 and normally urge it to the position shown.

v collapses the Sylphon towards the right in Fig. 3, ,i

Aclosed by a. cap 86, into which the air tube. I1 isv fitted at the endopposite to that connected with l the nozzle I8. The cap also carries anapproy nozzle.

priate nipple, etc., 91, for connection with the air pipe 32, thusestablishing the complete air line from the primary or atomizing airpump to the At each side of the nipple 81, and slightly above, arev openinsulated fittings 88 to admitl wires 89, the inner ends of which aresecured to the electrodes 2| by nuts 90, (Fig. 4).

Beneath the nipple 91 the cap 86 has an opening 9| to admit the heatertube 92 which surrounds the heater 20, and the oil line I9, leading tothe nozzle I8. Suitable mounting for the electrical connections and theend of the oil pipe I3 are provided by a large cast fitting 93, securedto the cap 86.- l A Forked pedestals 94 (Figs. 3 and 4) have openings`95and 96 to receive the air pipe I1 and the heater tubeI 92 and clamps 31to receivethe insulating tubes 98 for the electrodes 2|. Projections 99on the clamps 98 and a leg |00 engage the inside of the draft tube andform a support for the assembly bound together by the pedestals 94. Byremoving the fastenings for the cap 86 this When pressure of the air inthe chamber I2 lt-will move the piston to the right and compress thespring I|6. When the pressure'in the chamber I2 is relieved, thevspringI|6 willmove the parts back towards the position shown in Fig. 3 andunder proper conditions will shut off the oil from the burner andconnect the oil pipe 39 with the bypass 42, Fig. 1.

The shut off movement ofthe piston 43 produces a partial vacuum in theright end of the `cylinder 40, which is relieved through the passage 9(Fig. 3) by flow from the nozzle and prevents dripping at the orifice.Thus as an incident to stopping the flow of oil to the burner when thesupply of atomizing air is insufllcient, there is a slight withdrawal ofoil from the nozzle that prevents dripping and a correspondingaccumulation in the vcylinder which is immediately forced towards thenozzle when the airoperated shut olf valve is again shifted to permitthe oil to ilow to the burner,

' The motor and secondary fan The casing of the electric motor 22 isprovided with a shouldered flange II'I (Fig, 3) to nt wall assembly,called in practice the drawer assembly, l may be withdrawn as a unitfrom the draft tube.

The delivery end of'the draft tube is equipped with a suitableconverging tting |0I (Fig. 4) to direct the secondary air against themixture of oil and primary air` discharged from the nozzle I8. Thevdetailed Aconstruction ofthe nozzle, its connection with the' primary-air pipe |1, the oil pipe I9 and its operation in use will besufllciently clear from the enlarged section in Fig. 5, without.specific description. p The size of the orice, the spray angle and suchlike will vary with conditions and personal preference. l y Therectangular portion 15 of the main casing surrounding the lubricatingoil space, is provided at one side in Fig.`2, with a non-breakable sightglass |02, through which the lubricating oil can be readily observed inorder to maintain it at the appropriate level indicated by the line |03.

The air operated shut-01T valve for oil Referring to Fig. 3, it will beseen that the cyl'- inder 40 'of the air operated piston valve,described in-connection with the diagram, Fig, 1, has a reduced portion|04, received in and secured fast to the hollow flange |05 of a disk|06, bolted to the main casing to close the opening 11. The Sylphonbellows 44 has one end |01 soldered, or otherwise properly secured tothe inner face of the'disk |06 and its opposite closed end |08,cooperates with the cartridge shaped plunger |09, the bottom of whichacts directly on the stem I0 of the piston valve and the wall of whichtelescopes over the nipple II I on the cylinder 4|l.l

The oil pipes 39 and 4| and the bypass pipe 42 are secured to thecylinder 40 by nipples |I2, ||3 and |I4, respectively (Fig. 3) whichconnections are threaded to nipples, which in turn, are

|I8 of the fan casing I5 and be secured to it by bolts. The motor shaft|I9 is tted into the hubs |20 of the secondary fan or blower. 23 whichis preferably of the Siroco type.

The primary air pump naled in the hub portions |26 and |21 of the disks|2| and |22. The disk. |22 has a cylindrical ange |28, which telescopeswith and is secured to the boss |29 on the slotted wall 26 of thehousing.

The eccentric rotor |24 is provided with four slots |30 (Fig. 11) toreceive reciprocating vanes |3I, the outer edges of which engage theinner perimeter of the ring |23, and serve to propel the air through thepump. The vanesl are urged radially outwardby springs |32 surroundingguide pins |33, extending through the shaft |25.

As will be seenfrom Fig. 7, the air inlet |34 in this instance isthrough the disk |22 and leads to a curved inlet' passage |35 (Fig. l2)open to the inside of the pump chamber. The outlet |36 for air leadsthrough the periphery of the disk I2| to a curved passage |31 (Fig. 1l)in communication with the pump chamber.

From this it will be apparent that rotating the shaft |25 clockwise inFig, 11 will cause the air to enter through the inlet passage |34 and becompressed by the vanes-|3| successively and driven through the outletinto the pipe 30 leading to the main housing, Fig. 1.

The disk |22 is provided with a bushing |38 in Vwhich the shaft `|25 isjournaled, and the disk asoma? A by the screw valve lu locked in placeby the nu:

|42. By adjusting that valve the bypassed air can be cut off orincreased in any amount to regulate the delivery of the pump toanything-within its capacity.

As heretofore stated, the Iscrew valve |4| is vadjusted to maintain somenormal pressure in the chamber I2, for example a normal pressure with#in the range of tive to twelve pounds. A feature of the present form ofthe invention, however, is that the moving parts of primary air pump 24are dimensioned with such liberal clearances that plentiful lubricationof the pump interior is required to cause and maintain the normal pres-ljacent surfaces of discs |2| and |22 (Fig. 7), or

between faces of rotor |24 and corresponding faces of the discs |2| and|22, or between faces of blades |3| and corresponding faces or walls ofslots |30. (Fig. 11.) The provision of'such clearance requires only theordinary skill expected inthis art. especially since the pressurecreated by theypump running without lubricant is not critical'. Toprevent actuation of the valve piston 43, it is sufficient that thepressure from the'pump drop to any value below five pounds and a minimumpressure of only one pound will lift oil from the sump a verticaldistance of over thirty inches. Thus the clearance in the working partsof the pump may be such as,.in the absence of lubricant. to drop theoutput pressure to any value between one and five pounds.

The oil pump Refer to Figs. 3,' 7, 8, 9 and 10. y

The casing of the oil pump 24 is formedf by a cylinder |43 integral withthe hub |25 of the primary air pump and a disk-like cylinder head |44secured by bolts. Within this cylinder |43 is a bronze rotor |45 keyedto the end of the shaft |25 by a pin |40. Adjacent to the end of theshaft |25. the rotor is provided with a transverse bore |41 in which isa double ended piston |40, the intermediate portion of which is cut awayto form a notch |49, which receives an eccentric pin |50, projectingthrough the disk ||,which bears against the end of the rotor |45. y

Refer to Fig. 10.

The inlet for oil |52 through the cylinder |43 is in communication witha curved inlet passage' |53 extending partially around the rotor |45coincident with the cylindrical bore |41. The outlet for oil |54 in thecylinder I 43 communicates with a curved outlet passage |55, alsocoincident with the bore |41 in the rotor I 45. y

From this it will appear that when the shaft G is driven, the doubleended piston |48 will reciprocate back and forth and oil entering thein-. let |52 will be forced out the outlet |54.

By changing the eccentricity of the pin 50, the stroke ofthe doubleended piston can be changed and thus the capacity ,orl lthe delivery ofthe oil pump can be varied within the limits of the `design. Toaccomplish this adjustment, the disk |5|, bearing the pin |50, isprovided with a slot H55 (Figs. 3a, 9 and 10) which receivesl guidingpins |51, carried by the head |44. And these pins allow the disk |5Irectilinear motion crosswise t-o the axis of the shaft |25, but norotation.

The end of the pin |50, opposite to that which engages the disk |5|, isprovided with a socket |55, which receives a crank pin |59 on the shaft|80, the reduced end portion |6| of which projects through the stuilingbox |62 on the head |44 and is equipped with the lever 50.

By rotating the shaft |60, the crank can be made to change theeccentricity of the pin |50 from nothing to the extreme within the rangeof the design and to that extreme in either direction, thus the strokeof the piston can be adjusted from neutral to maximum and the same pumpmay be made to act as a pressure pump or a vacuuxn pump or, in otherwords, the intake and exhaust sides can be reversed by simply rotatingthe shaft and the length of the stroke in either phase of operation canbe adjusted from zero to a maximum.

In this particular liquid fuel burner system the pump will not bereversed, butit will be adjusted from varioussmall capacities to thelargest within the limit of the design, and that is accomf plished inthe organization shown in Fig. 1 bythe operation of thelever 58 throughair pressure or the spring 50 in the cylinder 50.

Referring again to Fig. 3, it will be seen that the shutter 21 for thesecondary air is rotatably mounted on the cylindrical flange |20 bywhichv the pump assembly is mounted on the main housing. lI'heconnection allows free rotation of the shutter without unnecessary playin opera- |54 and provided with va clamp |55 made fastk by bolts |40.This means of mounting it affords readyadjustment in connection with thestops 50 and 5|.

' For convenience in manufacture and assembly the three pumps and themotor for driving them have a common axis. 'I'he shaft for the primaryair pump and theoil pump is in one piece and is connected with the shaftof the secondary air fan 23 by a yielding flexible coupling |51.

4The oil pump here disclosed has a positive displacement and,beingdouble acting, its delivery for a given adjustment and speed isconstant for all practical purposes. For that reason, when it is used asa metering pump theapparatus can operate successfully in No. 5 oil.

The use of a double ended piston also has the advantage of giving therequired capacity` in very small size. y

When the stroke of the piston is increased by movement of the lever 50,as described, the delivery of oil tothe nozzle is positively increased.The increased delivery of oil results automatically in increased airpressure in the air line as required for proper atomization of theincreased oil flow. In a domestic oil burner adjusted for a normalpressure of five pounds in the primary chamber 2, the pressure in thechamber' has been observed to build up as high Vas ten pounds when therate of fuel delivery is substantially increased.

One reason for the automatic rise in pressure is that the increased flowof oil at thev burner nozzleoffers increased resistance to 'air flowfrom the nozzle thereby tending to increase air pressure in the air lineback of the nozzle.

At rst thought it wouldseem that the increase of air pressure resultingfrom increasing the oil ist owwould undesirably cause the modulatingmotor to shift the adjustment lever 58 in the direction for stillgreater increase in oil ow. However, the building up of primary airpressure due to the increased oil pressure does not .appreciably aiectthe operation of the modulating motor because it merely causes thepiston to move outwardly'a little more than it would otherwise, but thisexcess movement is very quickly compensated for by the reducedtemperature demand at assess? through the cli line to the nozzleregardless of the viscosity of the oil, valve means for bypassing oilfrom the delivery side of the oil pump to the the thermostat. 1 v

and cooperating with the pin |50, to shift it inA accord with the lengthof the stroke or capacity of the pump required. In that instance, and inother instances, some will wish to provide a spring |68 (Figs. 8 and 9)to constantly urge the pin |50 in one direction.

The automatic increase from low fire to high lire position will not workwith Minneapolis- Honeywell Relay 117 because the stack control willthrow the device on safety at low fire position. In such instances the R117 relay should be replaced by one of the many other controls as, forexample, those actuated by the light of the llame instead of the stacktemperature.

I claim: y

1. In an oil burner, the combination of a nozzle, fuel and primary airlines to the nozzle, a primary air pump for forcing air under pressureto the primaryj air line, a positive displacement variable capacity oilpump for supplying metered quantities of oil through the oil line to thenozzle regardless of the viscosity of the oil, valve means for bypassingoil from the delivery side of the oil pump. to the intake side thereofwhenever the primary air pressure is below. a predetermined value;andmeans for varying the amount of oil pumped by said oil pump in responseto burner load demand.v i

2. In an oil burner, the combination of a nozzle, fuel and primary airlines to the nozzle, a positive displacement'variable capacity oil pumphaving its discharge side connected to the fuel line, and means forIvarying the amount of oil pumped by said pump in response to burnerload demand, said means including a cylinder receiving air from theprimary air system through a restriction, a piston in the cylinderconnected with said pump for capacity control thereof, a spring opposingmovement of the piston in response to the pressure of the primary airline, said restriction serving to delay movement of the piston inresponse to an increase in the pressure of the primary air line.

3. In an oil burner, the combination of a nozzle, fuel and primary airlines to the nozzle, means, including a draft tube telescoped over aportion of said lines for supplying' secondary air to the space aroundthe nozzle, a primary air pump for forcing air under pressure to theprimary air line, a positive displacement variable capacity oil pumphaving its discharge side connected to said line for supplying meteredquantities of oil intake side thereof whenever the primary air pressureis below a predetermined value, and means for varying the amount of oilpumped'by said oil pump in response to burner load demand.

4. In an oil burner, the combination of a nozzle, fuel and primary airlines to the nozzle, means including a draft tube telescoped over aportion of said lines for supplying secondary air to the space aroundthe nozzle, a primary air pump for forcing air under pressureto the-primary air line, a positive displacement variable capacity oil pumpfor supplying metered quantities of oil through the oil line to thenozzle regardless of the viscosity of the oil, and means Afor startingthe. burner with a low llame and gradually increasing it to the sizerequired by burner load demand, said means including a device forgradually increasing the amount of oil pumped to the nozzle by said oilpump.

5. In an oil burner, thevcombination of a nozzle,

vfuel and primary air lines to the nozzle, means including a draft tubetelescoped over a portion of said linesfor supplying secondary air tothe space around the nozzle, a primary air pump for forcing air underpressure to the primary air line, a positive displacement variablecapacity oil pump. for supplying metered quantities of oil through ltheoil line to the nozzle regardless of the-viscosity of the oil, and meansfor starting ing a burner, means to deliver primary air to the Y burner,a secondary air passage tothe burner, means to deliver oil to saidburner, and means to deliver air to said secondary air passage, thecombination therewith of means to vary the Arate of oil delivery, meansto vary the rate of secondary air delivery, fluid-pressure-responsivemeans operatively connected with both of said delivery varying means,and passage means connecting said responsive means with said primary airpassage whereby said responsive means increases the rates of oil'andsecondary air delivery in response to the initial establishment ofoperating pressure in 'said primary air passage, said passage meansbeing restricted. to delay the response of said responsive means to saidestablishment of pressure.

'1. In a device of the character 'described having a burner, means todeliver primary air to the burner, a secondary air passage to theburner,

means to deliver oil to said b urner, and means to deliver air to saidsecondary air passage, the

ondary air delivery, iiuid pressure responsive means operativelyconnected with both of said delivery varying means, and passage meansconnecting said responsive means with said primary air passage wherebysaid responsive means increases the rates o f oil and secondary airdelivery l in response to the initial establishment of operatingpressure in said primary air passage, said asomar kpassage means being'sumciently restricted both to delay response of said responsive meanstosaid establishment of pressure and to retard the rate of responsethereby to cause the increase of oil and air delivery to occur graduallyover a period of'tlme after a delay period.

8. In a device of the character described having av burner, meanstodeliver primary air to the burner, a secondary air passage to theburner, means to deliver oil to said burner, and means to deliver air tosaid secondary air passage, the combination therewith by means to varythe rate of oil delivery, means to vary the rate of secondary airdelivery, iluid-pressure-responsive means operatively connected withboth oi' said delivery varying means, passage means connecting saidresponsive means with said primary air air pump for supplying primaryair. to the burner. means for supplying secondaryair to the burner,

' means. comprising an air. vmotor responsive to passage whereby saidresponsive means increases the rates of oll and secondary air deliveryin re- -sponse to the initial establishment of operating pressure insaid primary air passage, said passage means being restricted to delaythe response of said responsive means to said establishment of pressure,a. bleeder passage from said fluid-pressure-responsive means, means tocontrol the rate of ilow through said ybleeder passage thereby todetermine the adjustment of said responsive means relative topressurein'said primary air passage and means to operatesaid controlmeans in' response to the demand for heat.

9. In an oil burner, the combination oi a nozzle,

fuel and primary air linesto the nozzle, a positive displacementvariable capacity oil pump -having its discharge side connected to thefuel nected with said air passage for response to pres-.

sure therein, a second fluid-pressure-actuated means connectedwith said`air passage for reprimary air pressure andincluding a restriction in theprimaryair line leading to the air motor for starting the burner with alow flame and then relatively gradually increasing the supply of oil andsecondary air until the flame reaches its desired size. and meansforthereafter varying size of ame with the demand for heat.

13. In a device of the class described, a burner, means for supplyingair to the burner, modulating means comprising an air motor responsiveto primary air pressure and including a restriction in the primary airline leading to the air motor for starting oil feed to the burner at arelatively low rate for starting the burner with a low llame,andjautomatic means responsive to such initiation of oil feed toincrease the'oil feed relatively graduallyuntil the flame reaches adesired size, saidv modulating means thereafter varying the size of thellame wtih the demand for heat.

' 14. In a device of the character described, a burner, an oil passageto the burner, means to deliver air under pressure to said oil passage,means todeliver oil to said passage after delivery of air thereto isstarted thereby to increase the air pressure in the passage by athrottling action, said oil delivery means-including means operatinginitially to deliver oil to the nozzle at a minf imum rate to support alow burnerv flame, and means responsive to said increase in pressure insaid passage to increase the rate of oil delivery ata relatively gradualrate thereby to increase the burner -ilsme to a desired size, and meansfor thereafter fully modulating the size of .the flame with the demandfor heat.

15. In an oil burner, the combination of a nozzleffuel and primary' airlines to the nozzle, a

primary air pump for forcing air under pressure to the primary air line,a positive displacement variable 'capacity oil pump for supplyingmeteredv quantities of voil through the oil line to sponse to pressuretherein, a nrst control means responsive to said first fluid pressuremeans effective to-inltiate oil delivery to said oil `passage at apredetermined rate for starting said burner,

determined rate to a desired operating rate.

l1. In adevlce of the character described,` a burner, an oil passage tothe burner, an air passage to the burner, means to deliver oil to saidoil passage, means to deliver air to said air passage, a firstfluid-pressure-actuated means connected with said air passage forresponseto pressure therein, a second iiuid-pressure-actuated meansconnected with said air passage for response to pressure therein, afirst control means responsive to said first iluid pressure meanseffective to initiate oil deliver to said oil passage at a predeterminedrate for starting said burner, a second control means responsive to saidsecond iiuid pressure means effective to increase the rate of oildelivery gradually from said predetermined rate to a desired operatingrate, and means to vary the responsiveness of said second control meansin response to demand for heat.

12. In a device of the class described, a burner, an oil pump forsupplying oil to the burner, an

nozzle, fuel and primary. air lines to the nozzle.

a primary air pump forforcing air under pressure to the primary airline, a positive displacement variable lcapacity oil pump. for supplyingmetered quantities of;` oil through the oil line to the nozzleregardless of the viscosity of the oil..

adjustable means for supplying secondary air around the nozzle, meansfor shutting off the flow of oil to the nozzle whenever the primary airpressure` is below a predetermined value, and

means for varying the amount of oil pumped by I saidl oil pump and thevolume ofsecondary air v delivered around the nozzle in response toburner load demand.

i7. In a device of the class described, a burner, an oil pump forsupplying oil to the burner, an air pump for supplying primary air tothe burner, means for supplying secondary air to the burner, meanscomprising an air motor responsive to primary air pressure and includinga restriction in the primary air line leading to the air motor forstarting the burner with a low flame and then relativelygraduallyincreasing the supply of oil and secondary air until the-flamereaches its desited size, means for thereafter varying the size theamount of oil delivered to the nozzle in responseto burner demand, saidmodulating means including an air motor responsive to primary airpressure vand operativelyconnected to said oil delivery means,adjustable means for preventing' the air motor from cutting down thesupply of oil to the nozzle below a'predetermined minimum, andadditionalV means for completely shutting oi the ilow of oil to thenozzle when the 'burner motor is not in operation.

19. In an oil burner, a nozzle, means for delivering oil to the nozzle,means including a burner A an air chamber with a wall thereof movable inmotor for delivering primary air under pressure to said nozzle, andmeans for modulating the amountl of oil delivered to the nozzle inresponse to burner demand, said modulating means includl ing an airmotor responsive to primary air presnozzle below a predeterminedminimum, adjustable means limiting the volume iiow of oil to the nozzleunder maximum oil burner demand, and additional means for completelyshuttingfoi the ilow of oil to the nozzle when the burner motor is notin operation.

20. In an oil burner, a nozzle, means for delivering oil to the nozzle,means for delivering primary air under pressure to said nozzle, and

means for modulating the amount of oil de-v 2l. In an oil burner, anozzle, means for delivering oil to the nozzle, means for deliveringprimary air under pressure to said nozzle, and means ,for modulating theamount of oil delivered to the nozzle in response to burner demand, saidmodu- 1 lating means including an air motor having an air chamber with aWall thereof movable in `response to air pressure in the chamber andoperatively connected to'said oil delivery means to control the g amountof oil fed to the nozzle, and means for connecting the air chamber tothe primary air delivery means through a restricted orice, lsaid orificebeing adjustable as to size to thereby vary the responsiveness of theair motor to rapid increases in primary air pressure.

22. In an oil burner, a nozzle, means for delivering oil to the nozzle,means for delivering primary air under pressure to said nozzle, and

means for modulating the amount of oil delivered to the nozzle inresponse to burner demand, said modulating means including an air motorhaving -response to air pressure in the chamber and operativelyconnected to said oil delivery vmeans to control the amount `of oil fedto the nozzle, means for connecting the air chamber to the primary airdelivery means through a'restricted orice, and means for bypassing therestricted orice to obtain a quick equalization of pressure between theair chamber and the primary air delivery means whenever there is'arelatively quick drop in pressure in said latter means.

23. In an oil burner, a nozzle, meansfor fielivering oil to the nozzle,means for delivering primary air vunder pressure to said nozzle, andmeans for modulating the amount of oil delivered to the nozzle 1nresponse to burner demand, said modulating means including an air motorhaving an air chamber with a. wall thereof movable in response to airpressure in the chamber and operatively connected to said oil deliverymeans to control the amount of oil fed to the nozzle, means forconnecting the air chamber to the primary air delivery means through arestricted orice, and means for bypassing the restricted orlce to4obtain a quick equalization of pressure between the air chamber and theprimary air delivery means whenever there is a relatively quick drop inpressure in said latter means, said bypass means around the oriiiceincluding an air passage between the air chamber and the primary airdelivery means and a check valve in said passage.

24. In an oil burner, a nozzle, means for delivering oil to the nozzle,means for delivering primary air under pressure to saidA nozzle, andmeans for modulating the amount of oil delivered to the nozzle inresponse to burner demand, said modulating means including an air motorhaving an air chamber with a wall thereof movable in response to airpressure inthe chamber and operatively connected to said oil deliverymeans to control the amount of oil fed to the nozzle, means forconnecting the air chamber to the primary air delivery means through arestricted orice,

`and means for quickly releasing the pressure in the air .chamberwhenever the burner is stopped.

25. In an oil burner, a nozzle, means including a positive displacementpump for deliveringA u oil to the nozzle at rates independent ofviscosity changes, means for `deliveringI primary `air under pressure tosaid nozzle, means for supplying secondary air to the vicinity'ofthe'nozzle in a predetermined volume relationship to the rate at whichoil is being fed to the nozzle, means for modulating the amount of oildelivered to the nozzle andv the secondary air delivered in vitsvicinity in response to burner demand, saidv modulating means beingconstructed and arranged so that throughout its range of operation itsubstantially maintains the predetermined volume relationship betweenthe oil and secondary air being delivered to and in the vicinity, re,-spectively, of the nozzle'.

EARL JOSEPH SENNINGER.

@eminente ci" cmfecten Patent N o 2,397,987 April 9, 1946 EARL JSEPHSENNNGER i l it is hereby certified .that error eppears in the printedspecification of the wbove numbered patent requiring correction esfollows: Page 7, first column, line 12, claim 8, for the Words therewithby read therewith of; and that the seid Letters Patent should he readWith this correction therein that the same may conform to the record ofthe cese in the Patent Gee. v

Signed. and sealed this 4th dey of Junes A. D., 3.94@

iene@ LES FR i F'ifst Assistant @ammissioner of Patents.

